Mixture of polychloroprene, vinylidene chloride-acrylonitrile copolymer, and butadiene-acrylonitrile copolymer



i atenteci- Apr. 3, 1951 ga ns MIXTURE OF POLYCHLOROPRENE, VINYL- IDENE CHLORIDE-ACRYLONITRILE CO- POLYMER, AND BUTADIENE-ACRYLONI- TRILE COPOLYMER Ralph J. signer, Chicago, and Keith F. Beal, Berwyn, Ill., assignors to The Visking Corporation, Chicago, 111., a corporation of Virginia No Drawing. Application January 14, 1947, Serial No. 722,082

available. A film produced from any of the afore- V mentioned synthetic resins does not possess the necessary properties of flexibility, high resistance to tear, high elongation, capacity to return after elongation, high tensile strength, high resistance to moisture vapor penetration and to penetration by gases, as are required for the packaging of foodstuifs. Attempts were made to improve the physical properties of such films by the incorporation of a liquid plasticizer in the composition from which the films are produced. However, films containing a liquid plasticizer are unsatisfactory for the reason that such liquid plasticizers migrate from the resin or disappear by evaporation, leaving the resin embrittled, and frequently contaminate the contents of the package especially if the contents of the package is a foodstulT.

' In the course of research to improve the properties of films produced from synthetic resins mentioned, attempts were made to prepare films of resinous compositions containing a plurality of synthetic resins. However, when attempts were made to form a resinous composition of polychloroprene with vinylidene chloride-acrylonitrile copolymer, it was found that such resins were incompatible or incompatible in proportions which are necessary to give the desired results.

An object of this invention is to make a plurality of resins, which are normally incompatible in desired proportions, compatible.

Another object of this invention is to provide a' resinous composition containing a plurality of resins normally incompatible in the desired proportions and a blending agent which will make such'resins compatible.

An additional object of this invention" is to provide formed structures formed of normally incompatible resins but which are compatible in the structure.

A further object of this invention is to provide resinous formed structures having improved physical properties.

A specific object of this invention is to provide films formed of resinous compositions having physical properties which render them suitable for use as a packaging material.

Other and additional objects'will become apparent hereinafter.

The above objects are accomplished, in general, by incorporating in a resinous composition, containing a plurality of synthetic resins in proportions at which such resins are normally incompatible but which are necessary to obtain the desired properties, a blending agent whereby a homogeneous resinous composition is obtained from which the desired formed structure is prepared and in which structure the synthetic resins are compatible.

The blending agent, in general, is a synthetic resin as will hereinafter be more fully explained.

Usually, the synthetic resin components and the blending agent are dissolved in a solvent or solvent mixture whereby a homogeneous solution is obtained. Herein the term solvent covers a single solvent or a solvent mixture. No precise sequence for dissolving the resins and blending agent in the solvent is required. The resin components and blending agent can be added separately or simultaneously to the solvent, After the desired solution has been prepared, it is processed depending on the desired formed structure. In one embodiment of the invention, the resinous composition is formed into the desired formed structure and the solvent evaporated therefrom. In another embodiment, the resinous composition is extruded or cast into a precipitating bath; in which the resins are insoluble and with which the solvent is miscible, and thereafter the precipitated resinous article dried.

The nature of the invention will become more apparent by reference to the examples hereinafter set forth, wherein the proportions are by weight. It is to be understood that the examples are merely illustrative embodiments of the invention and that the scope of the invention is not restricted thereto. For convenience, the

3 specific synthetic resins and specific blending agents of the examples are designated by their respective trade names, the identity of which is set forth in the following table:

15 parts Neoprene CG, 39 parts Saran F-120, and 6 parts Hycar OR-l were dissolved in a solvent mixture composed of l'l4 parts acetone and 228 parts dioxane. The resin solution was cast in thin films onto glass plates, and the sol: vent evaporated in air at 50 C. The dry films containing 25% Neoprene CG, 65% Saran F420 and 10% Hycar OR- were stripped from the plates.

Example 2 15 parts Neoprene CG, 33 parts Saran F-120, and 12 parts Hycar OR-15 were dissolved in a solvent mixture composed of 174 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of Neoprene CG, 55% Saran F-120 and 20% Hycar OR-l5.

Example 3 18 parts Neoprene CG, 33 parts Saran F-120, and 9 parts Hycar OR-l5 were dissolved in a solvent mixture composed of 1'74 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of Neoprene CG, 55% Saran F-120 and 15% Hycar OR-15.

Example 4 (A) 21 parts Neoprene CG, 33 parts Saran F-l20, and 6 parts Hycar OR-l5 were dissolved in a solvent mixture composed of 1'74 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 35% Neoprene CG, 55% Saran F-120 and 10% Hycar OR-l5.

(B) Same as in (A), except that 1.2 parts 1,10-decanediamine dissolved in a small amount of dioxane were added to solution and the film dried in an air oven for 4 hours at 100 C. whereby the Neoprene CG was vulcanized.

Example 5 2'7 parts Neoprene CG, 27 parts Saran F-120,

and 6 parts Hycar OR-l5 were dissolved ina' solvent mixture composed of 1'74 parts acetone and 228 parts dioxane. Films were prepared and 228 parts dioxane.

from this resin solution by the method set forth in Example 1. The dried films consisted of 45% Neoprene CG, 45% Saran F- and 10% Hycar OR-15.

Example 7 28.5 parts Neoprene CG, 28.5 parts Saran F-120, and 3 parts Hycar OR-15 were dissolved in a solvent mixture composed of 1'74 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 47.5% Neoprene CG, 47.5% Saran F-120 and 5% Hycar DR-15.

Example 8 27 parts Neoprene CG, 2'7 parts Saran F-120, and 6 parts Hycar OR-25 were dissolved in a solvent mixture composed of 1'74 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 45% Neoprene CG, 45% Saran F-l20 and 10% Hycar OR-25.

' Example 9 21 parts Neoprene CG, 36 parts Saran F-120, and 3 parts Hycar OR-15 were dissolved in a, solvent mixture composed of 174 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 35% Neoprene CG, 60% Saran F-120 and 5% Hycar OR-15.

Example 10 24 parts Neoprene CG, 30 parts Saran F420, and 6 parts Hycar OR-15 were dissolved in a solvent mixture composed of 174 parts acetone Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 40% Neoprene CG, 50% Saran F-120 and 10 Hycar OR-15.

Example 11 30 parts Neoprene CG, 12 parts Saran F-120, and 12 parts Hycar ORr-15weredissolved in a solvent mixture composed of 1'74 parts actone and- 228 parts dioxane. Films wereprepared from thisv resin solution by the method set forth in Example 1. The dried films consisted of 60% Neoprene CG, 20% Saran F-l20 and 20% Hycar Example 12 28 parts Neoprene CG, 44 parts Saran F-l20, and 8 parts Hycar 0R-1 5 were dissolved in a solvent mixture composed of" 300 parts acetone,

Example 13 18 parts Neoprene CG, 39 parts SaranF-120,

and 3 parts Hycar 0R-l5 were dissolvedinv a.

solvent mixture composed of 297 parts acetone and 51.5 partstetrahydrofuran. A tape was cast in a water bath by the method describedinExample l2. The final tape consisted of 30% Neo,- prene CG, 65% Saran F1 20 and 5%, Hycar. OR-15.

TABLE II Physical Properties of Film Example: Tensile Elon- Tear Film Moisture Oxygen strength, gation, strength, thickvapor translbs. per per grams per ness transmissq. in. cent 1/1000" (mils) mission 1 sion 2 470 312 2.38 0. 81 28. fi 385 373 1.86 1. 82 12.8 386 339 1. 70 1. 54 9. 6 350 212 1.88 1. 4. 6 392 118 1. 76 0.78 9.8 340 88 1. 88 1. 47 12.7 309 48 1.41 2. 40 26. 9 210 7 l. 09 l. 66 32. 5

1 Moisture vapor transmissiongrams water per 24 hours per 100 square inches.

2 Cubic centimeters gas per 24 ll'lllS per 100 square inches.

Testing methods used in determining values for Table II latter is a liquid medium, which precipitates the resin from the solution. The precipitating bath is also one which in admixture with the solvent will form a mixture which is a non-solvent for the resin. Though many liquid substances and solutions can be used as the precipitating bath,

. water is preferred because of its economy.

Tensile strength-Scott Inclined Plane Tensile Strength Tester. A sample 1 inch lon by A inch wide is used. Tensile strength as used in Table II is given in pounds per square inch based on original cross-section area of the sample.

Elongation.Determined on the same machine and sample as tensile strength.

Tear strength.Thwing-Albert Research Type Tearing Tester. An initiated tear through a 1 inch length of film is used. Tear strength is recorded in grams per /10oo inch film thickness.

Moisture vapor transmission.Determined by General Foods Method as described in Modern Packaging, November 1942. Transmission given in grams of water passing through an area of 100 square inches of film in 24 hours.

Oxygen transmission-Determined by method and apparatus described in Paper Trade Journa 118, No. 10, 32 (1944). Transmission recorded as cubic centimeters of gas passing through an area of 100 square inches of film in 24 hours.

No special method of preparing the solution of the synthetic resins and blending agent is necessary. separately or simultaneously to the selected solvent. The mass is preferably agitated until solution is complete. The solution can also be facilitated and hastened by the application of heat.

As shown by the examples, the solution can be extruded and the solvent evaporated therefrom, or the solution can be extruded into a bath which is a precipitating agent for the resins and preferably also is miscible with the solvent of the composition.

The solvents which can be employed in the production of shaped articles from the solution are not restricted to those of the examples. When, for example, an article is to be prepared by the .process wherein the solvent is evaporated, any volatile solvent in which all of the resins are soluble can be used. When the article is to be prepared by a method wherein the solution is extruded into a precipitatingbath, any solvent in which all the resins are soluble, and which preferably also is misciblewith the precipitating bath, can be used. Generally, such solvent is volatile so that, upon drying of the article, the residual solvent will be evaporated.

In the embodiment of the invention wherein the solution is extruded into a precipitating bath, the

The components can be added either The total resin concentration in the solution is not restricted to those set forth in the examples. In general, when the solution is to be processed by a procedure wherein the solvent is evaporated from the shaped article, the total resin (including blending agent) can vary within limits. Usually, a total resin concentration of 10% to 30%, and preferably about 15%, is used.

For wet casting operations, i. e. when the solution is extruded into a precipitating bath, a solution viscosity of 10 to 25 seconds by the falling ball method is desired (this represents the time required for a steel ball to fall vertically through 8" of the resin solution). A solids content of approximately 15% to 25% is required to give such a viscosity.

Instead of blending through the use of solvents,

the various latices can be mixed and thereafter coagulated and subsequently heated and/or milled.

sired, the composition can contain any filler, reinforcing pigment, age resistors, accelerators, and.

vulcanizing ingredients which are ordinarily used in vulcanizing rubber or synthetic rubber. When such a composition is used, the film, after or during drying, can be vulcanized in the known manner. By the appropriate selection of the vulcanizing agents, one or all of the vulcanizable constituents can be vulcanized to itself or to each other. vulcanization of a specific constituent depends on the concentration of such ingredient and the use of the vulcanizing agent which will vulcanize only such ingredient. Example 4 (B) is illustrative of that embodiment wherein only one component (Neoprene) is vulcanized.

Various other substances may be included in the formula, such as softening agents, plasticizers, etc., although in general these may not be desirable.

Furthermore, anti-blocking materials, such as paraffin, stearamide, natural waxes, synthetic waxes, stearic acid, cetyl acetamido, ethylene bis palmityl amide, dicetyl ether and their homologues, may be incorporated to improve the surface properties.

As is disclosed in Examples 1-13 inclusive, resinous mixtures of polychloroprene and vinylidene chloride-acrylonitrile ccpolym'er (75% vinylidene chloride 'and 25% acrylonitrile) are made compatible by a blending agent which is 1,3 butadicneacrylonitrile copolymer. In Example 1 7 and 9-11 inclusive, the blending agent is 1,3 butadieneacrylonitrile copolymer (45% acrylonitrile), and in Example 8 the blending agent is 1,3 butadieneacrylonitrile copolymer (35% acrylonitrile) However, in this embodiment of the invention, the blending agent is not restricted to such butadieneacrylonitrile copoloymers. In general, a 1,3 butadiene-acrylonitrile copolymer containing from 25% to 45% acrylonitrile can be used as the bending agent.

Prior to this invention, due to the incompatibility of polychloroprene and vinylidene chlorideacrylonitrile copolymer, it was found impossible to use mixtures containing more than 1 part polyeacetate;

7 e lmioprene. o 3 arts in lide echloride-acme lq itr e c po ymen S ratnst, t: was qimd. t h a d tio Qt.- asma amount t; athi d. resin, suclr-v as. a copolymer of butadiene-acrylonitrile bove st b d', pe mits far. reater amount-of thechloroprene to be used Asshown,

lized in proportions. i, e. greater than. 1- partot polychloroprene to 3- parts' of; vinylindene chloride-acrylonitrile copolymer, at which such resins are incompatible, In general, the composition can contain 25% to 60% polychloropreneand.65% to 25% vinylidene chloride-acrylonitrile copolymer.

Various solvents are disclosed in Examples 1- 13 inclusive, but it is to be understood thatthe invention is not restricted thereto. Any solvent as hereinbefore described can be used. In addition to those set forth in the examples, other illustrative solvents for solutions to be processed by the evaporative method are tetrahydrofuran, a mixture composed of 62% by weight of acetone and 38% by weight of dioxane, and preferably :a mixture composed of 85% to 75% by weight of acetone and to by weight of tetrahydrofuran. Higher ketones, such as methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone can be substituted for acetone in the previously mentioned mixtures.

The aforementioned solvents can also be used in wet extrusion processes wherein water constitutes the precipitating bath.

Though the invention has been previously described particularly in connection with the, pro.- duction of film, it is to be understood that the invention is not restricted thereto. The. solutions also can be used for the preparation of self-, sustaining continuous film in the form of continuous seamless tubing. Likewise, the solutions hereinbefore described can be used in the production of other shaped structures, such as filaments, yarns, fibers, caps, bands, etc. Additionally, the solutions can be employed as a coating composition for the coating of various base materials, such as paper, fabric, metal foil, regenerated cellulose, polyvinyl alcohol, nylon, zein, ethyl cellulose, cellulose acetate, etc. Still further, the soutions can be used as a sealing cement for gasproof seals of resinous sheet materials, as a cement for sealing film; of polyv-inylidene chloride and its copolymers, as a gasket cement, etc.

Self-sustaining film in the form of continuous sheeting or seamless tubing produced from the components of synthetic resins, herein described, are characterized by high resistance to moisture vapor penetration and to penetration by gases. Because of these properties, a film of the synthetic resins hereinbefore described is admirably suited for use in wrapping and packaging of any product which is desired to be protected.

In addition to the foregoing properties, a film of the synthetic resins hereinbefore described is transparent, thermoplastic, heat-scalable, resilient, has a high tensile strength, has a fair amount of. elcnsat on, s r ntabl c nta ns. no ub ta wh-ieh.w 1:afiq l e dor ta t Qt hermd: uct wrapped therein or Will migrate from thefilm into the product wrapped; therein, resists exudation of fatty substances, and is highly resistant to puncture, all ofv which properties render the material particularly suitable for packaging or wrapping. of foodstuffs.

Herein and in the claimsv the proportions are by weight unless otherwise specified.

In the claims, the term consisting essentially of is intended to cover the named ingredients with or without the modifying ingredients herein disclosed.

Since it is obvious modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted theretp except as set forth in the appended claims.

We claim:

1. Formed structures consisting essentially of a mixture of polychloroprene and a" copolymer consisting of vinylidene chloride and 25% acrylonitrile, said polychloroprene and said copolymer. being present in proportions" in'which they are normally. incompatible, and 5% to 20% of a blending agent consisting of a'copolymer of 1,3 butadiene. and 25% to 45% of acrylonitrile whereby. said incompatible polychloroprene and vinylidene chloride-acrylonitrile copolymer, are made compatible.

2 Formedstructures consisting essentially of a mixture of polychloroprene and a copolymer consisting of 75% vinylidene chloride and 25% acrylonitrile, said polychloroprene and said copolymer being present in proportions. in which they are. normally incompatible, and 5% to 20% of. a blending agent consisting of a copolymer of 1,3 butadiene, and 35% of acrylonitrile whereby said incompatible polychloroprene and vinylidene chloride-acrylonitrile copolymer are made compatible.

3 Formed structures consisting essentially of a mixture of polychloroprene and a copolymer consisting of 75% vinylidene" chloride and 25% acrylonitrile, said polychlo rcprene and said copolymer being present in proportions in which they are normally incompatible, and 5%'to 20% of a blending agentconsisting oi" copolymer of 1,3 butadiene and 45% of acrylonitrile whereby said incompatible polychloropreneand vinylidene chloride acrylonitrile, copolymer aremade compatible 4. Formed structures consisting essentially of a mixture of 25% to 6.0% of polychloroprene and 65% to 25% of a copolymer consistingof 75% vinylidene chloride and 2 5% acrylonitrile, said polychloroprene and said copolymer being present in proportions in which said polychloroprene and said copolymer are normally incompatible, and 5% to 20% of a blending agent consisting of a copolymer of 1,3 butadiene and 25% to 15% acrylonitrile whereby said incompatible polychloroprene and vinylidene chloride-acrylonitrile copolymer are made compatible.

5. Formed structures consisting essentially of a mixture of 25% of polychlo'roprene and 65% of a copolymer consisting of 75% vinylidene chloride and 25% acrylonitrile and in which proportions said polychloroprene and saidcopolymer are normally incompatible, and 10% of a blending agent consisting of a copolymer of 1,3 butadiene and 45% of acrylonitrile whereby said incompatible polychloroprene and vinylidene chloride-acrylonit i e c ymer a mad om a ble that various changes and 6. Formed structures consisting essentially of a mixture of 30% polychloropi ene and 55% of a copolymer consisting of 75% ifinylidene chloride and 25% acrylonitrile and in which proportions said polychloroprene and said copolymer are normally incompatible, and 15% of a blending agent consistingof a copolymer of 1,3 butadiene and 45 of acrylonitrile whereby said incompatible polychloroprene and vinylidene chloride-acrylonitrile copolymer are made compatible? 7. Formed structures consisting essentially of a mixture of 45% of polychloroprene and 45% of a copolymer consisting of 75% vinylidene chloride and 25% acrylonitrile and in which proportions said polychloroprene and said copolymer are normally incompatible, anq- -10% of a blending agent consisting of a copolymer of ,3 butadiene and 45% of acrylonitril -whereby said incompatible polychloroprene and vinylidene chloride-acrylonitrile copolymer aremade compati ble.

J. SIGNER. KE' HF. BEAL.

REFERENCES The following references are of record in the file of this patent:

UNITED STATES i fA'rEN'rs Nnmber Name Date 2 ,247,154 Geiger June 24, 1941 2,319,959 Tierney May 25, 943 2,456,454 Signer Dec. 14, 1948 OTHER REFEREQ c'Es Garvey et al.: Ind. and Eng-'9 Chem. 36, pp.

209-211, Mar. 19, 1944. 

1. FORMED STRUCTURES CONSISTING ESSENTIALLY OF A MIXTURE OF POLYCHLOROPRENE AND A COPOLYMER CONSISTING OF 75% VINYLIDENE CHLORIDE AND 25% ACRYLONITRILE, SAID POLYCHLOROPRENE AND SAID COPOLYMER BEING PRESENT IN PROPORTIONS IN WHICH THEY ARE NORMALLY INCOMPATIBLE, AND 5% TO 20% OF A BLENDING AGENT CONSISTING OF A COPOLYMER OF 1,3 BUTADIENE AND 25% TO 45% OF ACRYLONITRILE WHEREBY SAID INCOMPATIBLE POLYCHLOROPRENE AND VINYLIDENE CHLORIDE-ACRYLONITRILE COPOLYMER ARE MADE COMPATIBLE. 